Metal Collecting Tank for a Heat Exchanger, Especially for Motor Vehicles

ABSTRACT

The invention relates to a metal collecting tank ( 1 ) for a heat exchanger, especially for motor vehicles. Said collecting tank is produced by non-cutting shaping from a steel sheet blank, preferably an aluminum sheet, and the collecting tank ( 1 ) comprises two approximately parallel sidewalls ( 1   c,    1   d ) and narrow walls each and an upper side ( 1   b ) and at least one connecting piece ( 3 ). According to the invention, the at least one connecting piece ( 3 ) is configured as one piece with the collecting tank ( 1 ) and is shaped from the steel sheet blank.

The invention relates to a metal collecting tank for a heat exchanger, especially for motor vehicles, according to the preamble to patent claim 1.

Metal collecting tanks are utilized at the present time for heat exchangers of motor vehicles, especially soldered radiators and soldered coolant coolers and, to be precise, for reasons of recycling and physical strength. Prior to this development resulting in individual types of heat exchangers, plastic tanks were used as the collecting tanks and distribution tanks of radiators and coolant coolers, which plastic tanks offered the advantage, among other things, that connecting pieces could be injection-molded onto the plastic tanks in a single piece. This facility does not exist in the case of metal water tanks, which are preferably manufactured from aluminum sheet by non-cutting shaping, such as deep-drawing. On the contrary, metal tanks for heat exchangers exhibit only a single, inward-formed or outward-formed sheet metal collar, which is soldered to a pipe coupling, via which a connection to a heating or cooling circuit of the motor vehicle is possible.

Previously disclosed in DE 197 52 139 A1 by the applicant was a soldered radiator for a motor vehicle with metal collecting tanks, into which an inlet connecting piece and an outlet connecting piece are soldered. These connecting pieces are executed in this case mainly as pipe couplings, so-called plug-in fork couplings, as previously disclosed in DE 44 03 402 A1 by the applicant. In this case, the pipe coupling exhibits on the one hand a cylindrical area, which is inserted into a collar in the metal water tank and is soldered to it in a leakproof manner. On the other hand, the pipe coupling (also referred to as the connecting piece) exhibits an extended area, into which a pipe end of a heating line is capable of being inserted, sealed by means of a sealing ring and fixed axially by means of a plug-in fork coupling. This kind of pipe connection to a metal collecting tank requires a large number of component parts, that is to say a collecting tank with a collar formed thereon, a pipe coupling (connecting piece) capable of being soldered to the collecting tank including sealing and locking means, and a pipe end of the connection line.

Similar pipe couplings, also referred to as a pipe connection or a pipe connection coupling, in particular with a plug-in fork coupling, were previously disclosed in DE 196 21 282 A1 and DE 196 21 283 A1 by the applicant. A variant of a pipe connection coupling having an elastic retaining clip ring was previously disclosed in DE 196 48 162 A1 by the applicant—here, too, the pipe coupling is in the form of a cup inserted and welded in place in a metal collecting tank. The connection with the pipe end of the connecting line is effected by means of a sealing ring and the retaining clip ring, which is supported on a bead at the end of the pipe.

The object of the present invention is to manufacture a metal collecting tank of the kind mentioned by way of introduction more simply and at lower cost, in particular having regard for the one or more pipe connections.

This object is achieved through the characterizing features of patent claim 1. It is provided according to the invention that at least one connecting piece is capable of being manufactured in a single piece from the collecting tank and its starting blank. The one or more connecting pieces are formed in this way from a sheet metal blank by non-cutting shaping, such as hole punching, multi-stage deep-drawing and/or upsetting. The associated advantage is that an expensive operation, such as soldering of a pipe coupling and/or a pipe connection piece to the collecting tank, is avoided. This results in lower manufacturing costs for the collecting tank and accordingly for the entire heat exchanger, for example a radiator or a coolant cooler for a motor vehicle. The connecting piece according to the invention can thus be connected directly to a connecting pipe or to a connecting hose.

In an advantageous embodiment of the invention, the connecting pieces can be arranged on the long sides or on the upper side of the collecting tank. The connecting piece is preferably of circular cylindrical configuration, which can be represented most easily by non-cutting shaping process steps.

In a further advantageous embodiment of the invention, the connecting piece exhibits an encircling bead, which is capable of being manufactured preferably by upsetting the connecting piece. The advantage of an axial fixability of the connecting piece in question, a connecting pipe, a pipe coupling or a connecting hose is achievable in this way.

In one advantageous embodiment of the invention, the connecting piece exhibits an external diameter D and a length L, in conjunction with which the proportion of the length L to the diameter D lies in the range from 0.8 to 1.0, and preferably 0.9. A connecting piece with these dimensions offers the possibility of producing a pipe connection involving the use of means that are previously familiar from the prior art. The not inconsiderable thinning of the material due to stretching in the direction of the longitudinal axis of the connecting piece necessarily results in a reduction in the original wall thickness of the sheet metal blank. The use of a multi-stage shaping process, however, makes it possible to maintain a minimum wall thickness that is required for reasons of physical strength.

According to a further advantageous embodiment of the invention, the connecting piece according to the invention, in particular with an encircling bead, is capable of connection by means of a pipe coupling of a previously disclosed kind to a heating or cooling circuit of a motor vehicle. The pipe coupling can be secured in relation to the bead, for example by means of a plug-in fork coupling. A pipe or a hose of the coolant circuit is connected to the pipe coupling.

Illustrative embodiments of the invention are depicted in the drawing and are described in greater detail below, where:

FIG. 1 illustrates a front view of a collecting tank for a soldered radiator having two connecting pieces arranged on the upper side;

FIG. 2 illustrates the collecting tank according to FIG. 1 as a view from above;

FIG. 3 illustrates a section III-III through a connecting piece of the collecting tank;

FIG. 4 illustrates a front view of a second illustrative embodiment of a collecting tank having laterally arranged connecting pieces;

FIG. 5 illustrates the collecting tank according to FIG. 4 as a view from above;

FIG. 6 illustrates a section VI-VI through a connecting piece of the collecting tank, and

FIGS. 7-9, which are similar to FIGS. 1-3, illustrate an alternative embodiment of the present invention.

FIG. 1 depicts a metal collecting tank 1 for a soldered radiator of a heating system (not illustrated here) for a motor vehicle. The collecting tank 1 exhibits an open under side 1 a, which is connected with positive engagement to a tube base of the radiator (not illustrated here). Arranged opposite the open under side 1 a is a lightly upwardly curved upper side 1 b, which exhibits two connecting pieces 2, 3, via which the radiator (not illustrated here) is capable of being connected to the heating circuit, that is to say a coolant circuit for an internal combustion engine. Present between the two connecting pieces—although not illustrated here—is a separating wall, so that one connecting piece functions as an inlet connecting piece and the other connecting piece functions as an outlet connecting piece for the coolant. Each of the two connecting pieces 2, 3 exhibits an encircling bead 2 a, 3 a.

FIG. 2 depicts the collecting tank 1 as a view from above, which illustrates the circular cross sections of the connecting pieces 2, 3 and the encircling beads 2 a, 3 a. The floor plan of the collecting tank 1 is essentially of rectangular configuration and exhibits two long sides 1 c, 1 d and two narrow sides 1 e, 1 f, each of which blends into the other with a radius.

FIG. 3 depicts a section in the plane III-III in FIG. 1, that is to say passing through the connecting piece 3. As can be appreciated from the graphical sectioned view, the connecting piece 3 is executed in a single piece with the collecting tank 1, that is to say it is formed from the upper side 1 b. The entire collecting tank 1 including the two connecting pieces 2, 3 is capable of being manufactured in a single piece from a plane sheet metal blank, preferably an aluminum sheet or a sheet made from an aluminum alloy, by non-cutting shaping, that is to say in a number of process stages such as stamping, hole punching, deep-drawing and upsetting. According to the invention, the material of the upper side 1 b, in particular a circular and lightly outwardly curved surface F, is drawn into a collar in this case and, to be precise, in the direction of the longitudinal axis a of a connecting piece. Before the collar-drawing or deep-drawing of the connecting piece 3, a circular opening should advantageously be stamped into the surface F from the curved upper side 1 b in the region of the longitudinal axis a. Thinning of the material by stretching to a length L and to an external diameter D then takes place by the use of a suitable plunger. The bead 3 a is formed in the connecting pieces 3 by upsetting. In a preferred illustrative embodiment, the connecting piece 3 (as well as the connecting piece 2) exhibits an external diameter D of about 18 mm and a length L of about 17 mm. This results in a proportion for L/D in the order of 0.94 mm. Taking the original, curved surface F with a diameter of about 18 mm as the starting point, the cylindrical surface of the connecting piece 3 with dimensions π×D×L achieved by shaping is about three times as large, where no account is taken of the bead 3 a. The starting material before the shaping of the connecting piece is thus stretched by a considerable amount and is enlarged with regard to its surface, with the result that a reduction takes place in the material thickness, although this can be limited by a corresponding number of intermediate stages in the shaping process, at least to the extent that it is possible to maintain a minimum wall thickness that is required for reasons of physical strength. In the preferred illustrative embodiment, the wall thickness of the starting material, that is to say an aluminum sheet, is in the order of 1.5 mm. The external diameter D_(s) of the bead is in the order of 1.3 times the diameter D of the connecting piece, that is to say in the order of 23.4 mm. For technical reasons associated with the shaping process, it is also important to provide a radius R, in the order of 1.5 mm or more, in the transitional zone between the upper side 1 b and the cylindrical connecting piece 3.

FIG. 4 depicts a further illustrative embodiment of the invention for a metal collecting tank 4 with two connecting pieces 5, 6, which are arranged on a long wall 4 a of the collecting tank 4 and—as in the previous illustrative embodiment—are also executed in a single piece from the collecting tank 4 and the long wall 4 a. The collecting tank 4 is also produced from an essentially plane sheet metal blank, preferably an aluminum sheet, having a wall thickness in the range from 0.5 mm to 2.0 mm, by non-cutting shaping, that is to say essentially by deep-drawing. The collecting tank 4 can also be connected with positive engagement to a soldered radiator (not illustrated here).

FIG. 5 depicts the collecting tank 4 in a view from above. Each of the connecting pieces 5, 6 exhibits encircling beads 5 a, 6 a. The collecting tank 4 is again of approximately rectangular configuration and exhibits two long sides 4 a, 4 b arranged parallel to one another, which are connected to one another by an upper side 4 c.

FIG. 6 depicts a section on the plane VI-VI in FIG. 4 through the connecting piece 6. The graphical sectioned view shows that the connecting piece 6 (as well as the connecting piece 5) are executed in a single piece with the walls 4 c and 4 a of the collecting tank 4, that is to say they are formed from the wall of the collecting tank and the sheet metal blank serving as the starting material. As in the previous illustrative embodiment, shaping takes place in a number of suitable process stages in order to avoid excessive distension and/or an unacceptable reduction in the wall thickness. The dimensions of the connecting piece 6 are essentially the same as in the illustrative embodiment according to FIG. 3, that is to say the connecting piece exhibits a length L in the order of 16 mm and an external diameter D in the order of 18 mm. The bead exhibits a diameter D_(s) of approximately 1.3 times the diameter D of the connecting piece. The result of these dimensions—as in the previous illustrative embodiment—is a considerable increase in the order of 2 to 3.5 times in the surface area of the starting material to be shaped. In this case, too, the metal sheet thickness of the starting material is in the order of 1.5 mm for aluminum sheet or sheet metal made from an aluminum alloy.

The depicted connecting pieces—according to both the first and the second illustrative embodiments—are preferably capable of being connected via a pipe coupling with a connecting pipe to a heating circuit of a motor vehicle. For example, a pipe coupling of the kind that is previously disclosed in the aforementioned DE 44 04 402 A1 by the applicant through FIG. 4 could be used. The connecting piece depicted there could be pushed with its extended coupling area over the connecting piece with a bead according to the invention and secured axially by means of a plug-in fork coupling, which must be arranged behind the bead of the connecting piece. The connecting pipe of the heating circuit could be secured at the other end of the pipe coupling and/or the connecting piece, for example by soldering. This represents only one possible connection of the connecting piece according to the invention, however. It would also be possible, for example in the case of coolant coolers, to push a coolant hose over the connecting pieces according to the invention and to secure this to the connecting piece by means of a clip. 

1. A metal collecting tank for a heat exchanger, especially for motor vehicles, capable of being manufactured in particular by non-cutting shaping from a sheet metal blank, preferably an aluminum sheet, the collecting tank in each case exhibiting two long sides and narrow sides arranged approximately parallel, as well as an upper side and at least one connecting piece, wherein the at least one connecting piece is executed in a single piece with the collecting tank and is capable of being formed from the sheet metal blank.
 2. The collecting tank as claimed in claim 1, wherein the at least one connecting piece is arranged on the upper side.
 3. The collecting tank as claimed in claim 1, wherein the at least one connecting piece is arranged on one long side.
 4. The collecting tank as claimed in claim 1, wherein the at least one connecting piece exhibits a circular cross section and an approximately cylindrical form.
 5. The collecting tank as claimed in claim 1, wherein the at least one connecting piece exhibits an encircling bead that is capable of being manufactured in particular by upsetting.
 6. The collecting tank as claimed in claim 5, wherein the at least one connecting piece exhibits an external diameter D and a length L, and in that the proportion of L/D lies in the range from 0.8 to 1.0, and preferably 0.9.
 7. The collecting tank as claimed in claim 6, wherein the diameter D lies in the range from 15 to 20 mm, and the sheet metal blank exhibits a metal sheet thickness in the range from 0.5 to 2.0 mm.
 8. The collecting tank as claimed in claim 6, wherein the length L lies in the range from 15 to 20 mm, and the sheet metal blank exhibits a metal sheet thickness in the range from 0.5 to 2.0 mm.
 9. The collecting tank as claimed in claim 5, wherein the bead exhibits an external diameter D_(s), and in that the proportion of the bead diameter D_(s) to the diameter D of the connecting piece is in the order of 1.3.
 10. The collecting tank as claimed in claim 1, wherein the at least one connecting piece is capable of being connected via a pipe coupling to a heating or cooling circuit of a motor vehicle. 